Wear-resistant throat plate for knitting machine



July 2, 1963 G. T. SMITH 3,095,718

WEAR-RESISTANT THROAT PLATE FOR KNITTING MACHINE Filed Sept. '7, 1960 f/ ff INVENTOR hm, 4 hw f www ATTORNEYS United States This invention relates to a yarn guiding element ,for use on knitting machines or the like and is concerned more particularly with a wear-resistant thi-oat plate for association with such machines, especially circular machines of the type sold by Fidelity Machine Co.

The increasing use in the textile art of synthetic yarns, for example, nylon and Daeron, especially those of lower denier, and the trend towards handling such yarns at higher land higher speeds has aggravated the problem of reducing the wear of surfaces with which these yarns come in contact in the various textile machines by which they are processed and has given impetus to the development of wear-resistant elements for use at those points of the machines Where Wear is unusually acute. Thus, ceramic inserts have been 'developed for a variety of the more conventional devices by which yarn is guided and/or handled, such as thread guides employing eyelets, tubes, rollers, pig-tails, condensors, and the like. The techniques and expedients utilized in applying inserts to such conventional guards, however, are of little assistance in devising a similar solution to the problem of yarn wear on the throat plates of circular knitting machines. As

is Well known, the plate bridges the throat of the latch n ring of the machine and delivers the yarn from the yarn fingers to the needle cylinder. This plate is generally of channeled configuration in the direction of travel of the yarn, which, dur-ing the operation of the m-achine, traverses the width of the channel and leaves its front edge in a generally downward direction. The combination of the back and .forth movement of the yarn and the angle with which it leaves the plate subjects the front edge of the plate to extreme wear, especially fat its side corners. This wear necessitates `frequent replacement of the plate and, moreover, limposes an abnormally high iiuctuati-ng tension on the yarn.

From what has just been said, it will be appreciated that the coniigurationof the conventional plate is distinctly diierent from that of the usual type of yarn guide and this has hampered the `adaptation of wear-resistant ceramic inserts for throat plates. In addition, as the machine operates, the throat plate is subjected to an unusually high level of vibration which precludes the use of :adhesive as the sole means of retaining a ceramic insert in place upon the plate.

As a solution to these problems, there was developed a novel form of throat plate as disclosed in application Serial No. 818,149 for Yarn Guide Element tiled June 4, 1959, commonly assigned with the present application, now U.S. Patent 3,004,733, wherein an `insert of wear-resistant ceramic material was disposed within a tapered recess at the forward edge of the throat plate land was provided with lateral extensions or wings overlapping the front margins of the plate and restraining the insert against downward movement relative to the plate, a design that has proved quite satisfactory. The throat plate in this instance, however, was specifically developed for use with the so-called Model KN circular knitting machine manufactured and sold by Scott and Williams, Inc. and, while the throat plates of other like machines can be modiiied by the addition of an insert in a similar manner, certain other machines require a sufciently diiferent type of plate as to make the utilization of the concept of the above identified application impractical. One such machine is the Fidelity atent ICC G-Needle 2-Speed circular machine sold by the Fidelity Machine Co. The throat plate of this particular machine includes an elongated oval aperture disposed in closely spaced relationship to the iront edge of the plate and extending generally transversely to the direction of Inovernent of the yarns through the plate. The presence of this aperture at this particular location introduces rather unusual problems in modifying the design of the ear-lier application.

The principal object of the present invention is the provision for a circular knitting machine of a throat plate including a wear-resistant ceramic insert constituting the forward yarn-contacting edge of the plate, with the insert joined to the plate by tongue-and-groove connection, preferably at each of its ends, which plate can be employed in lieu of the plate described in the aboveidentified application.

:A :further object of the invention is a throat plate having a wear-resistant ceramic insert united to the body of the plate by a tongue-and-groove Iconnection as just described in which said connection is rein-forced by a pin passing through the insert and a portion of the plate body to prevent the insert from becoming dislodged during use.

.An additional object of the invention is a throat plate las in the preceding object `wherein the reinforcing pins terminate ush with one face of the plate, which face in the normal operative position of the plate Iabuts a sur- -rface of the knitting machine whereby the pins can be displaced only when the plate is detached from the machine.

A further object of the invention is a throat plate, having a wear-resistant ceramic insert, which is :adapted for use with knitting machines of the type sold by the Fidelity Machine Co.

These and other objects and advantages will be apparent from the following detailed description when read in conjunction with the accompanying drawing, in which:

FIG. 1 is 'a-view in top plan of a throat plate modified in accordance with the present invention in which the plate Iand ceramic insert are shown in a position just preparatory to assembly;

FIG. 2 is a view similar to FIG. 1 but with the plate and insert assembled;

FIG. 3 is a bottom plan view of the assembly of FIG. 2;

FIG. 4 is a cross-sectional View taken substantially along the line 4-4 of FIG. 2; Y

FIG. 5 is a cross-sectional view taken substantially along line 5-5 of FIG. 2;

FIG. `6 is an exploded view in perspective of the throat plate of the invention;

FIG. 7 is a View in side elevation of the modiiied throat plate of the invention in actual yWorking position on the latch ring of the knitting machine, the other elements of the machine being omitted.

Turning now to a description of the invention with reference to the drawings, the numeral 10 generally indicates the portion of the conventional throat plate 'which is retained for purposes of the invention, which portion may be referred to for convenience =as the base member. It will be seen that this portion is in the shape of a relatively thin, rectangular block having parallel top and bottom faces 12 and 14, respectively, parallel side faces 16 and 18, and a rear end face 20 disposedat right angles to the Walls 12u18. Intermediate side walls 16 and 18, top Wall 1,2 is cut away to provide a recess, generally design-ated 22, which is dened by a oor wall 24 and upstanding parallel end walls 26 and 28. The sections of base member l on either side of recess 22 lare formed with elongated apertures 30, 32 normally extending perpendicular to faces 12, 14, through which apertures screws 35 may be inserted to attach base member to the underside of the latch ring `33 (see FIG. 7) of the knitting machine. The base member may, of course, be adjusted relative to the latch ring and needle cylinder within the limits of :apertures 33, 32. The portions of bottom face 14 of the base member marginal to apertures 3), 32 are counter-sunk as at 34 to receive the heads of the retaining screws 35.

As is known in the art, base member l() may be formed of steel or the like although, if desired, other material may be substituted, such as nylon or nylon reinforced with a steel supporting plate as is disclosed in the previously-identiiied application.

Customari-ly, the entire throat claim, which has essentially the same overall configuration .as the assembly shown in FIGS. 24 is constructed as a unitary article and there is provided in the lfloor a recess 22, a transverse elongated aperture stopping just short of the side walls 26, 28 of the recess. In accordance with the present invention, however, the front end portion of the base member, except as hereinafter explained, is cut away andreplaced by a correspondingly formed portion of wear-re sistant ceramic material, which is referred to herein, for convenience, as an insert member and is given the general designation 40. The plane along which the conventional throat plate is foreshortened to define the base member of the present invention may, of course, vary somewhat in its location from fron-t to rear of the plate, but preferably, that plane passes through the major axis of the aperture in the floor of recess 22 so that the front face 37 of member l@ `includes an inwardly curved portion 38 which defines one-half of that recess.

As is best shown in FIGS. l, 4 and 6, the sections of the front face 37 on either side of recess 22 `are each pro vided with a relatively thin fiat tongue, indicated by the numerals 42, 44, by means of which insert member it? may be attached to base member 16. Tongues 43, 44 preferably extend parallel to faces l2 and 14 of member l() at a locus lying approximately midway between these faces and have their outer edges lying more or less iiush with side faces 16 and 1S of the base member and with their inner edges terminating somewhat short of the limits of recess 22. The axes of the tongues preferably make a right angle with the plane of front face 37. Each tongue is provided with 1an aperture i6 having its axis generally at right 4angles to the top and bottom faces of member for a purpose toe-be hereinafter explained.

As already indicated, insert member 4Q corresponds in configuration to the portion that is cut away from the conventional throat plate to leave base member iti. Thus, the insert member includes top and bottom faces 52, 54, side faces '56, 58 and a recess 62 bounded by a floor wall 64- and upstanding parallel side walls 66, 68, all of which Walls and faces lie Hush with the corresponding walls and faces of base member '10 when the insert member and base member are `assembled together to constitute an entire throat plate. Along its front face 70, the insert member is smoothly curved in a manner similar to the conventional throat plate for reasons well known in the art. To complete the center aperture defined in part by the inwardly curved portion 38 when the two members are fitted together, the rear face .of insert member di@ is formed with a correspondingly shaped central portion 72, the portions 3S, 72 together constituting an elongated more or less oval recess, as is readily apparent in FiG. 2.

Obviously, insert 70 must be adapted to effect mating engagement with tongues 42, 44 when assembled with base member l1t) and, to this end, the rear or inner face of the insert is formed at its lateral extremities with corresponding recesses 74, 76 so configured `as to receive tongues 42, 44. To avoid any possibility of the insert member becoming ydislodged from the base member after assembly, the portion of the insert member overlying each of the recesses 74, 76 is penetrated by an aperture 7S in axial alignment with the corresponding aperture 46 in the tongues 42, 4d, and after the two members are assembled together with the tongues and recesses in mating engagement, a small rigid retaining pin 8l) is inserted into each of the apertures to lock the tongues in place. lf desired, apertures 78 may be extended downwardly into the portion of the insert member underlying the recesscs 74, 76 but it is preferred that these apertures do not pass completely through the insert member. Consequently, pins 8d can be inserted and removed only from the top face of the insert. Since, when the plate is in operative position on the lmitting machine, the top face lof the plate on either side of recess 22, 62 abuts against the underface of the latch ring of the machine, it will be seen that there is no possibility of retaining pins becoming accidentally unseated from their Aapertures while the machine is in operation.

It is desirable in most instances to employ a filler, preferably of an adhesive nature, between the contacting surfaces of the insert and base members. Such a filler Serves primarily to insure a proper fit between these surfaces which fit, in the absence of a filler, would be diflicult and impractical to achieve. Obviously, the filler is not relied upon as the primary means for connecting the two members together although, wherever it is of an adhesive nature, it does offer a further guarantee against the two members coming apart. As a practical matter, an adhesive joint cannot be relied upon alone since in time such a joint will become weakened by oil penetration or by machine vibration so as to allow the insert member to drop ofi into the knitting cylinder and cause an expensive smash-up. In accordance with the present invention, there is no danger of this occurring; even if the adhesive liller does become weakened, the two members are positively held together by the tongue-and-slot retaining pin connection.

It is preferred that the tongues of the tongue-and-slot connection be carried by the base member since the material from which that member is constructed is better able to withstand the load of supporting the insert member, than is the rather brittle ceramic of the insert member. As a less desirable alternative, however, the arrangement of the tongue and slots can be reversed with the former being integral with the insert member and the latter provided in the base member.

The insert of the present invention was designed for specific application to knitting machines available from the Fidelity Machine Company and details of the plate have been illustrated accordingly. It does not necessarily follow, however, that the principles of the invention are limited to this single application; as a matter of fact, they will be found useful in connection with various other throat plates or, for that matter, with any yarn guide wherein a strong, positive connection between a wearresistant insert and a base member is a desirable feature.

While ceramic materials suitable for the construction of Iwear-resistant insert of the present invention are sutiiciently well known in the art that a detailed description thereof is hardly necessary, duplication of the invention may `'be facilitated by the knowledge that this type of material is described in U.S. Patents 2,2l4,703 and 2,369,666 to Thurnauer. In general, ceramics having properties satisfactory to the `manufacture of the inserts according to this invention may be identied by the following characteristics:

Hardness, Mobs scale 8-9. Resistance to impact, Charpy,

pounds per square inch 2.4-6.3. Flexional strength, pounds per square inch 20,000-40,000. Compressive strength, pounds per square inch 80,000l00,000. Density, pounds Iper cubic inch .O-.123. Water absorption Nil. Resistance to heat 1,09()o C.-l,1()0 C.

Thermal conductivity .01E-.02.

Specic ceramics meeting this definition can be obtained from the American Lava Corporation under the trade name ALSIMAG.

Some examples of the variations and modifications within the scope of the present invention have already been mentioned and those skilled in the art can appreciate that others can be made without rdeparting from the spirit of the invention. Consequently, the scope of the invention should be `interpreted in the light of the appended claims rather than the embodiment specifically illustrated and described.

Having ythus described my invention, what is claimed 1s:

1. A wear-resistant yarn guide comprising a base member and an insert member formed of wear-resistant ceramic materials arranged in abutting relation, at least one tongue projecting from one of said members, a recess formed in the other of said members for each such tongue and adapted to receive the same, aligned apertures formed in the tongue and in an adjacent portion of said other member, the latter aperture having an opening in only one face of the member, the axis of said apertures extending generally transversely of the tongue axis, and a rigid retaining pin inserted into said apertures through said opening, said pin passing at least substantially through said tongue and extending into said other member on at least one side of the tongue.

2. A yarn guide `as in claim 1 wherein said 'base member is provided on one face thereof Iwith a recess through which said yarn passes and said insert member includes on its corresponding face a recess constltutmg an exten- 5. A yarn guide as in claim 3 wherein the plane of the abutting faces extends at a right angle to the axis of said recesses.

6. A throat plate adapted for attachment to the undersurface of the latch ring of a knitting machine, said plate comprising a base member to be attached to said ring undersurface, said member having a surface thereof abutting said undersurface when attached and an end face extending generally at right angles to said surface, an insert member of wear-'resistant ceramic material having an end face adapted to mate with the base member end face and disposed in abutting relationship therewith, one of said members having at least one tongue projecting from its end face and the lother of said members having a reces-s for each such tongue formed in its end face, aligned communicating apertures formed in each such tongue and the adjacent portion of said other member at an angle to the aforementioned base member surface, each aperture in said other member having an opening only in said base member surface, and a rigid retaining pin for each such tongue inserted into said apertures through said opening, said pin Ipassing at least substantially through the corresponding tongue and extending into said other member on at least one side of such tongue, whereby the ring undersurface closes said opening `when the plate is in operating position.

References Cited in the le of this patent UNITED STATES PATENTS 916,553 Heap Mar. 30, 1909 2,436,904 Shea Mar. 2, 1948 2,896,434 McKinley et al. July 28, 1959 2,967,412 Hoefer Jan. 10, 1961 3,004,733 Spivey Oct. 17, 1961 FOREIGN PATENTS 451,288 Canada Sept. 21, 1948 

1. A WEAR-RESISTANT YARN GUIDE COMPRISING A BASE MEMBER AND AN INSERT MEMBER FORMED OF WEAR-RESISTANT CERAMIC MATERIALS ARRANGED IN ABUTTING RELATION, AT LEAST ONE TONGUE PROJECTING FROM ONE OF SAID MEMBERS, A RECESS FORMED IN THE OTHER OF SAID MEMBERS FOR EACH SUCH TONGUE AND ADAPTED TO RECEIVE THE SAME, ALIGNED APERTURES FORMED IN THE TONGUE AND IN AN ADJACENT PORTION OF SAID OTHER MEMBER, THE LATTER APERTURE HAVING AN OPENING IN ONLY ONE FACE OF THE MEMBER, THE AXIS OF SAID APERTURES EXTENDING GENERALLY TRANSVERSELY OF THE TONGUE AXIS, AND A RIGID RETAINING PIN INSERTED INTO SAID APERTURES THROUGH 